Enhanced 911 (or E911) service is a feature of the 911 emergency-calling system that automatically associates a physical address with a calling party's Automatic Number Identification (ANI). The enhanced 911 service provides emergency responders with the location of the emergency without the calling party having to provide it. A final destination of a 911 call (e.g., where the 911 operator is located) is referred to as a Public Safety Answering Point (PSAP). A calling party number (CPN) may be used to determine the ANI associated with the calling party. The ANI may be used to look up an address of the calling party, associated with the ANI, in a third party Automatic Location Identification (ALI) database that is secure and separate from the public telephone network. The determined address of the calling party may be used to locate the closest PSAP to the calling party in the emergency situation. The PSAP may receive emergency (or 911) calls and associated address information, and may respond to the emergency accordingly.
To enable E911 services for voice over Internet protocol (VoIP) subscribers, the VoIP subscribers must register their locations of their VoIP devices with a service provider for storage in regional ALI databases. When a VoIP subscriber makes a 911 call, the regional ALI databases may be queried to assist in accurate PSAP determination and to provide an emergency operator with the VoIP subscriber's location and callback number. Use of ALI databases assumes that a phone or device associated with the CPN is not taken to another location without re-provisioning service. However, in the case of wireless devices simulating wireline services (e.g., fixed wireless devices), a subscriber's VoIP device may be portable. If the VoIP subscriber becomes mobile, inaccurate location identification may be provided to the PSAP during an emergency call. Similarly, non-emergency services providers may offer other location-sensitive services for VoIP subscribers using portable devices, while still relying solely on the street address provided by the customer at the time of service activation.